Bonding, coating, and shielding processes are important in the material processing or molding, and a variety of materials are used for the material. Especially from the aspect of workability, materials having the properties capable of being added and coated at ambient temperatures and then cured by some action have been long used.
Most adhesives and paints are generally used such that pigments or resins are dissolved in an organic solvent or water to be coated on target materials in the form of liquid and then the organic solvent or water is evaporated to obtain cured products. However, using an organic solvent causes a problem of negative health effects or inflammability due to evaporated gas, and using water causes a problem of taking time in order to obtain a cured product due to the low volatility of water.
Among those materials, a photocurable material can cure a liquid composition only by irradiation of light, and is thus used as a useful material. In general, only a portion that is irradiated with light can be cured in the photocurable material, so that it is difficult to cure a portion that the light is hard to reach. Thus, a variety of chain transfer agents are used as additives in order to cure a portion at a certain distance (a dark portion) from the irradiation portion (e.g., see Patent Literature 1).